Note: Search is limited to the most recent 250 articles. To access earlier articles, click Advanced Search and set an earlier date range.To search for a term containing the '&' symbol, click Advanced Search and use the 'search headings' and/or 'in first paragraph' options.

Your Email

Message

Verification

Embed Video

Archaeo-astronomy of Southern Africa

The heavens have always fascinated humanity, and evidence of quite
sophisticated understanding of the movements of stars and planets,
including the alignment of sacred sites with particular heavenly
bodies or astronomical events, and dating back millenia, have been
found on every inhabited continent.

Of course, such observations and analyses were not undertaken for
anything remotely like modern science, but for religious and ritual
purposes, and determining the change of seasons. These activities
were often centred on 'complexes' or monuments of wood or stone, of
varying degrees of sophistication, which were probably both
'temples' and 'observatories'. The classic, and unusually complex,
example is Stonehenge in England, constructed in three phases
between 3000 BC and 1500 BC, the main axis of which is aligned with
the midsummer sunrise, and an observer in the centre of the complex
can determine both when summer is at it height and winter is at its
deepest.

Simpler equivalents to Stonehenge have been found all over the
world – so, are there any in South Africa? We don't yet
know.

Oddly, hardly any work has been done on this field, known as
archaeo-astronomy, in Southern Africa.

A local pioneer in this discipline is Richard Wade who has
established the Nkwe Ridge Observatory to the east of Pretoria, and
he has so far focused his researches on Great Zimbabwe, although,
as he points out, there was a cultural unity linking what is now
the Republic of Zimbabwe with the Limpopo, Gauteng, Mpumalanga and
perhaps even Free State provinces of South Africa.

Before the advent of modern light and air pollution, the night
skies over the South African highveld gave, particularly in winter,
a superbly clear view of the stars and planets, and this brilliant
display must surely have impressed the indigenous African peoples
who saw it nearly every night.

Concerning Great Zimbabwe, Wade points out that a number of small
monoliths are embedded in the top of the eastern arc – that
is, facing sunrise, moonrise and star rise – of the main
enclosing wall, but none are found on the rest of
circumference.

Furthermore, standing atop the platform found at the eastern end of
the Great Enclosure, as it is called, one can see over the wall to
the horizon.

To someone standing on that platform, three of the monoliths
clearly align with the three stars of the constellation Orion,
namely Saiph, Alnilam and Bellatrix, when they rise heliacally
(that is, just before sunrise) on the winter solstice (that is, the
shortest day of the year). The central of these three monoliths
also marks the central belt star of Orion, the start and end point
of the Venus synodic period, as well as the equinoxes.

(The equinoxes are those two days each year when day and night are
of equal length; the vernal equinox occurs on September 23 in the
Southern Hemisphere, and so can be regarded as marking the end of
winter, or the dry season, and the arrival of summer, or the rainy
season, while the autumnal equinox occurs on March 20.

The Venus synodic period lasts 583,9 days, divided into four phases
– appearance, which lasts 263 days, disappearance, 50 days,
apearance, 260 days, and disappearance, 8 days.) Furthermore, the
tip of the small conical tower found within the Great Enclosure of
Great Zimbabwe, when viewed from the platform, also aligns with the
vernal equinox sun at sunrise.

In fact, Wade has determined that there are 35 alignments of
heavenly bodies with the perimeter wall monoliths when viewed from
the platform, and he suggests that the platform originally had
emplaced, at its centre, a single monolith that could have been two
metres high, providing more precise alignments.

Most striking, however, is Wade's discovery that the large conical
tower in Great Zimbabwe, which dates from the 14th century, is,
when seen from the platform, in alignment with the supernova
remnant RX J0852.0-4622 in the constellation Vela. The point is
that RX J0852.0-4622 is now believed to have gone supernova some
time between AD 1300 and 1340, and would have been clearly visible
in the Southern Hemisphere. There is thus a most suggestive
correlation between the construction of the large tower and what
would have been a spectacular event in the heavens.

Clearly, archaeo-astronomy is a discipline in its infancy in South
Africa, but what is already obvious is that, when South Africans
look upwards to study the night sky, they are following in a
tradition that runs deep into the country's and region's past.